Sorry, but you do know that the Maximoffs originated in the X-Men continuity? Like, they share deep ties with that continuity. It's where they come from, and there are plenty of stories with them in it.

Yes, they are tied to the Avengers universe too, but that does not take away the fact they're still X-Men characters.

Every time I read someone say this I literally writhe on the inside.

Wanda and Pietro are NOT X-Men characters. This piece of misinformation based off of lack of knowledge on the characters' histories is annoying as hell to me. They are mutants, they are not X-Men characters. The reason Fox can use them is because they are mutants, not because they are X-Men characters. They are by every sense and context of the word, Avengers characters. Yes, they first appeared in X-Men, but that does not make them X-Men characters. The Inhumans, Black Panther, Ronan, and Nova Corps all appeared in Fantastic Four first, that does not make them Fantastic Four characters.

The Maximoffs are not just tied to the Avengers, they ARE Avengers. They're the oldest Avengers sans the original team. They have been Avengers for over 40 years. They have never been X-Men. They are in literally hundreds of Avengers issues and only a couple dozen X-Men issues. They've only recently even become heavily involved in X-Men storylines. What's happened in the past decade was NOT the status quo of the comics before then. The stuff with House of M and Avengers vs. X-Men is the most Wanda has ever been involved with X-Men.

Their ties with the X-Men do not run deep at all and are superficial at best. They were a part of the first incarnation of the Brotherhood of Evil Mutants for 3-4 issues and then left. They were not integral at all. Until they became Magneto's children 20 years after they were first introduced they didn't even have any real connections to anything going on in the X-verse.

Simply put, the twins belong with the Avengers. Their origin can only be told by Marvel, They are historically Avengers characters and have very little interaction with the X-Men. There are decades of material with them being Avengers and AT BEST a couple years worth of them even being involved with X-Men storylines, let alone being a part of them. Fox cannot do the characters as they are from the comics justice whatsoever. They would be different people if they were to be used in X-Men films.